Inclusion of off-normal incidence data in a low-energy electron diffraction crystallographic analysis for the Cu(100)-(2 × 2)-S surface structure

Abstract

A low-energy electron diffraction (LEED) crystallographic analysis has been undertaken to assess the lateral and vertical relaxations for the Cu(100)-(2 × 2)-S surface structure. The study uses five normal-incidence beams and seven beams with an off-normal direction for a polar angle of incidence equal to 8°. Both lateral and vertical relaxations in the copper structure are small (0.03 Å or less) compared with the structure in bulk copper, but the senses are unchanged from the recent normal-incidence analysis (H. C. Zeng, R. A. McFarlane, and K. A. R. Mitchell, Phys. Rev. B, 39, 8000 (1989)). The new LEED-determined S—Cu bond length is 2.23 ± 0.06 Å, while the S to topmost Cu interlayer spacing is 1.28 ± 0.03 Å.